There are devices and methods known according to which an electrical analog signal corresponding to the dead weight becomes subtracted from the gross weight and the difference voltage becomes processed further. The analog voltage corresponding to the dead weight value according to such known arrangement is produced by means of a potentiometer. In practice there have been difficulties encountered with such known apparatus in that in the event high accuracy is required an expansion in the magnitude of 10.sup.3 to 10.sup.4 cannot be set in a simple fashion to be represented with voltages which would be delicately sensitive and constant in nature.